Brake Booster Question On 1999 Corolla - Toyota Corolla, Chevy Prizm (1998-2008)

I have a 1999 corolla with possibly a bad brake booster.

The brake takes an enormous amount of force to depress, and I have replaced the booster twice without seeing a difference.

The first booster is a recycled part bought off ebay.

The second is a reman'd booster by cardone.

What are the chances of both boosters being bad? Should I get another replacement?

I've checked the booster hose and it seems to be fine. When I cover up the booster end of the hose with my finger while the engine running, I can feel there is suction, but it's a bit weak. Even when there is a small amount of vacuum, should the booster still work to an extent?

Thanks for everyone's help

Sure it is not an issue with the master cylinder or related vacuum hoses? From your description - it does sounds like a bad brake booster, to get two bad ones in a row is quite unusual though. Could be a bad check valve - sometimes those can bleed off vacuum before it gets to the booster.

Here is a quick check: Pump the brake pedal several times with the engine off (this will make sure ot bleed off any residual vacuum in the booster). Depress and hold your foot on the pedal, start the engine. If the booster is functioning properley - amount of force required to hold the pedal should lessen and the may drop slightly. If nothing happens - check the vacuum connections to the booster. If connections are OK, a new booster is likely needed.

Sure it is not an issue with the master cylinder or related vacuum hoses? From your description - it does sounds like a bad brake booster, to get two bad ones in a row is quite unusual though. Could be a bad check valve - sometimes those can bleed off vacuum before it gets to the booster.

Here is a quick check: Pump the brake pedal several times with the engine off (this will make sure ot bleed off any residual vacuum in the booster). Depress and hold your foot on the pedal, start the engine. If the booster is functioning properley - amount of force required to hold the pedal should lessen and the may drop slightly. If nothing happens - check the vacuum connections to the booster. If connections are OK, a new booster is likely needed.

Thanks for the reply fish.

There is just 1 vacuum hose that leads from the engine to the brake booster and it appears to be fine.

Is there any way to check the master cylinder for problems?

When I perform the test you suggested, nothing changes in the pedal feel when I start the engine. Maybe I have a bad check valve, but doesn't it come with the booster?

Thanks

I forgot to ask - ABS or no ABS?

Usually a bad master cylinder will manifest itself as the inability to hold pedal pressure (pedal slowly sinks to the floor). When you replaced the booster - di you check the push rod clearance? As for a bad check valve - you could get a brand new one that faulty to begin with or fails very quickly.

I forgot to ask - ABS or no ABS?

Usually a bad master cylinder will manifest itself as the inability to hold pedal pressure (pedal slowly sinks to the floor). When you replaced the booster - di you check the push rod clearance? As for a bad check valve - you could get a brand new one that faulty to begin with or fails very quickly.

Non-Abs.

I haven't experienced the pedal slowly sinking to the floor, so it's probably not the master cylinder.

No I did not adjust the push rod clearance. If the adjustment is off, could it cause the symptoms below?

I can depress the pedal a little over 1/2 way before it stops going further. Pressing the pedal multiple times with the engine off does not make the pedal harder to depress.

Thanks

I have a theory on the problem. I mentioned before that the vacuum was weak. Maybe it's too weak to allow the booster to function properly. If this is the case, what can I do?

HAve not enough or very low vacuum levels would explain much of your symptoms you are seeing. Could be a simple case of a cracked, collapsed or loose vacuum hose at the source, generally the intake manifold. I would start looking for vacuum leaks before they actually get to the booster - as there are a number of sources that require some sort of vacuum (ie., EVAP system), lots of potential culprits for a leak somewhere. As the 1999 Corolla is MAP based, poor vacuum at the engine would cause poor driveability - if the car runs pretty well, then you can concentrate on the hoses themselves.